The long term objective of the proposed research is to develop minimally invasive techniques for the detection of precancerous changes in tissue utilizing laser induced fluorescence (LIF). In this proposal, endoscope-compatible clinical systems will be developed for real time spectroscopic diagnosis of transitional cell carcinoma (TCC) in the urinary bladder, and colorectal dysplasia/carcinoma in chronic mucosal ulcerative colitis (MUC) and other settings. LEF from these selected tissues will be characterized, the spectroscopic features will be correlated with tissue morphology from fluorescence microscopy and microspectrofluorimetry studies, and decision schemes for accurate diagnosis of disease will be established utilizing morphologic/molecular models. The techniques developed in this investigation will be broadly applicable to the characterization of disease in many other tissue systems, and in the long term will provide the capability for real time in vivo diagnosis. This proposal focuses on the development of these methodologies for the direction of biopsy in the detection of precancerous chances in these tissues.